Air conditioning controller for a hybrid car

ABSTRACT

When the vehicle stops, a target blowout temperature, a temperature after evaporator, and a predetermined temperature which has been preset are compared with each other. Accordingly, when it is judged that cooling capacity is maintained, a &#34;start engine&#34; demand is not outputted. When it is judged that cooling capacity is not obtained, a &#34;start engine&#34; demand is outputted. After a &#34;start engine&#34; demand has been outputted, even when cooling capacity is maintained, an engine is not stopped. As a result, fuel wastage and annoyance causing to passengers by the engine that keeps on starting up when the vehicle stops can be prevented.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an air conditioning controller whichcontrols an air conditioner for a vehicle. More particularly, thepresent invention relates to an air conditioning controller for a hybridcar which has an electric motor in addition to an engine serving as apower source for motion of the vehicle.

2. Description of the Related Art

Usually, in air conditioners of vehicles, when an evaporator issufficiently cooled and when the cooling load is low, use of acompressor is refrained in order to save energy.

In recent years, a hybrid car having an electric motor which generatesdriving force through electricity in combination with an engine whichgenerates driving force through the combustion of fuel such as gasolineand the like has been proposed. Even when an engine is stopped, thishybrid car can travel by driving an electric motor with electric powersupplied from batteries. Further, batteries may be charged beforehand,or batteries may be charged by electric power generated through thedriving force from the engine while traveling.

Even in the aforementioned air conditioner in a hybrid car, a compressormust be driven whenever a vehicle interior portion is air-conditioned.For this reason, Japanese Patent Application Laid-Open (JP-A) No.6-286459 discloses that when an engine has been stopped, it can bestarted again by operating the driving switch of an air conditioner sothat a compressor is driven by the driving force of the engine.

Therefore, a motor for driving the compressor of an air conditioner isunnecessary. Further, it becomes possible to operate the air conditionerwithout making use of driving force generated from the electric motor orelectric power generated from batteries for operating the electricmotor.

In the hybrid car, when the vehicle stops, the engine stops.Accordingly, an engine can be prevented from being run unnecessarily inorder to improve fuel economy.

However, while the engine stops, if the operating switch of an airconditioner is switched ON when the engine is off, the engine starts up.Moreover, if the vehicle stops traveling with the air conditioner inuse, the engine keeps on running. As a result, wasteful consumption offuel occurs.

In order to prevent such fuel wastage, a way of starting an engine inconcert with the driving of a compressor has been thought of. However,an engine that keeps on starting up when a vehicle stops could annoypassengers.

SUMMARY OF THE INVENTION

In view of the aforementioned, it is an object of the present inventionto provide an air conditioning controller for a hybrid car in which theamount of fuel consumed through the operation of an air conditioner canbe reduced, and fuel economy can be improved.

The first aspect of the present invention is an air conditioningcontroller for a hybrid car, which is provided in the hybrid car beingequipped with an engine and an electric motor and having starting meansfor starting the engine in response to a "start engine" demand, andwhich controls an air conditioner for air-conditioning a vehicleinterior portion via a cooling cycle formed by a compressor and anevaporator, comprises temperature after evaporator detecting sensorwhich detects the temperature of air cooled by the evaporator, judgingmeans which judges whether the temperature after evaporator detected bythe temperature after evaporator detecting sensor is equal to or lowerthan a predetermined temperature, and stopping means which stops said"start engine" demand when the temperature after evaporator detected bythe temperature after evaporator detecting sensor is judged to be equalto or lower than a predetermined temperature.

In accordance with the first aspect of the present invention, when thevehicle stops, if the temperature after the evaporator is equal to orlower than a predetermined temperature, the engine does not start. Thepredetermined temperature may be a temperature at which it can be judgedthat minimum cooling capacity can be maintained without driving acompressor. Accordingly, the amount of fuel consumed for driving anengine can be reduced without deteriorating cooling capacity of an airconditioner. A predetermined temperature may be the temperature neededfor minimum cooling capacity or may be the higher of the temperatureneeded for minimum cooling capacity (a first temperature) and thetemperature of blowout air at the time when the aforementionedair-conditioned air is blown into a vehicle interior portion to regulatethe temperature of the vehicle interior portion to a set temperature (asecond temperature).

Further, as described above, a "start engine" demand may be canceledeven when the vehicle is either in a traveling state or in a stoppingstate. When the vehicle travels, the temperature needed for minimumcooling capacity is used as a predetermined value. When the vehiclestops, the higher of the temperature needed for minimum cooling capacityand the temperature of blowout air at the time when the aforementionedair-conditioned air is blown into a vehicle interior portion to set thetemperature of the vehicle interior portion to a set temperature (thesecond temperature) may be used as a predetermined temperature.

In accordance with the first aspect of the present invention, when ithas been judged by the judging means that the temperature after theevaporator exceeds a predetermined temperature, stopping of the "startengine" demand by the stopping means is canceled and a "start engine"demand is outputted to the starting means.

In this way, when the temperature after the evaporator exceeds apredetermined temperature, the engine is started. Accordingly, when thevehicle stops, sufficient cooling capacity can be maintained.

The first aspect of the present invention is an air conditioningcontroller for a hybrid car further comprising detecting means fordetecting whether a vehicle is stopped, wherein in a case in which whenit is detected by the detecting means that the vehicle has been stopped,the operation of the stopping means may be prohibited.

In this way, when an engine is started in order to obtain a coolingcapacity while the vehicle is stopping, the engine is kept on startingup.

Accordingly, annoyance caused to passengers by the engine that keeps onstarting up when the vehicle stops can be prevented.

The second aspect of the present invention is an air conditioningcontroller for a hybrid car, which is provided in the hybrid car beingequipped with an engine and an electric motor and having starting meansfor starting the engine in response to a "start engine" demand, andwhich controls an air conditioner for air-conditioning a vehicleinterior portion via a cooling cycle formed by a compressor and anevaporator, comprising, a temperature after evaporator detecting sensorwhich detects the temperature of air cooled by the evaporator, a vehicleinterior portion temperature detecting sensor which detects thetemperature of the vehicle interior portion, first judging mean whichjudges whether the difference between the temperature of the vehicleinterior portion detected by the vehicle interior portion temperaturedetecting sensor and a set temperature is greater than a predeterminedvalue, second judging means which judges whether the temperature afterthe evaporator detected by the temperature after evaporator detectingsensor is greater than a predetermined temperature in a case in whichthe result of the judgment by the first judging means is negative, andstopping means which stops the "start engine" demand in a case in whichthe result of the judgment by the second judging means is negative.

In accordance with the second aspect of the present invention, in a casein which the difference between the temperature of the vehicle interiorportion and the set temperature is equal to or lower than apredetermined value and the temperature after the evaporator is equal toor less than a predetermined temperature, namely, in a case in which thedifference between the aforementioned temperatures is equal to or lessthan an optimum temperature that makes human beings feel comfortable, a"start engine" demand is stopped and the engine is not started.Accordingly, the engine can be started at minimum of necessity. As aresult, the amount of fuel consumed for driving the engine can bereduced.

As described above, a "start engine" demand can be stopped in both casesin which the vehicle travels and stops. It can be detected by thedetecting means whether the vehicle has stopped. The detecting means isthe engine control computer which drives the engine or the vehicle speedmeans which detects vehicle speed.

In accordance with the second aspect of the present invention, in a casein which the difference between the temperature of the vehicle interiorportion and the set temperature is more than a predetermined value or inwhich the temperature after the evaporator is more than a predeterminedtemperature, stopping of the "start engine" demand by the stopping meansis canceled and a "start engine" demand is outputted to the startingmeans.

Accordingly, in a case in which the difference between the temperatureof the vehicle interior portion and the set temperature is more than apredetermined value or in a case in which the temperature afterevaporator is more than a predetermined temperature, the engine isstarted. As a result, even when the vehicle stops, sufficient coolingcapacity can be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural view of a hybrid car and an airconditioner which are applied to a first embodiment of the presentinvention.

FIG. 2 is a flowchart showing a drive demand control routine whichstarts when the air conditioner according to the first embodiment isswitched ON.

FIG. 3 is a flowchart showing a drive demand control routine whichstarts when an air conditioner according to a second embodiment isswitched ON.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description of a first embodiment of the present embodiment will begiven hereinafter. FIG. 1 shows a schematic structural view of a hybridcar 10 which is applied to the present first embodiment.

The hybrid car (vehicle) 10 has an engine 12 and an assist motor 14 asdriving source for the vehicle to travel. The driving forces of theengine 12 and the assist motor 14 are outputted to a driving wheel 16via a transmission (not shown). Accordingly, the hybrid car (vehicle) 10travels. A driving shaft 12A of the engine 12 is connected to the assistmotor 14 and a generator 20 via a planetary gear 18.

The generator 20 receives the driving force transmitted from the engine12 and thereby generates electric power. The electric power is directlysupplied to the assist motor 14, and via batteries which are not shown.Further, the assist motor 14 is rotated and driven in accordance withthe driving of the engine 12 by electric power which is supplied fromthe generator 20 and by electric power which is supplied via batterieswhich are not shown. The drive forces from the engine 12 and the assistmotor 14 are output to an output shaft 22.

The engine 12 and the assist motor 14 are connected to an engine ECU 24and are controlled by the engine ECU 24 so as to be driven. For example,the engine ECU 24 sets a target torque and a target rotational frequencyon the basis of the power to be output to the output shaft 22, andcontrols the engine 12 and the assist motor 14 so as to maintain the settarget torque and the set target rotational frequency.

The hybrid car 10 has an air conditioner (which is referred to an airconditioner 30) which is equipped with an air conditioning controller 26to which the present invention is applied. The air conditioner 30 has acooling cycle including a compressor 32, an evaporator 34, or the like.The compressor 32 is connected to a pulley 38 having an electromagneticclutch 36 provided at a rotation shaft of the pulley 38. The drivingforce is transmitted to the compressor 32 from the engine 12 via anendless driving belt 40 which is entrained around the pulley 38.

In the air conditioner 30, by the compressor 32 being rotated anddriven, refrigerant circulates in a cooling cycle and the evaporator 34is cooled.

The evaporator 34 is provided within an air conditioning duct 42. Aheater core 44 and an air mix damper 46 into which the cooled water issupplied from the engine 12 are provided within the air conditioningduct 42.

The air conditioner 30 suctions vehicle external air and vehicleinterior air into the air conditioning duct 42 by a blower fan (notshown). The suctioned air is cooled by the evaporator 34. The cooled airis partially supplied into a heater core 44 by the air mix damper 46.The air which has bypassed the heater core 44 and the air which haspassed through the heater core 44 and has been heated are mixed.Thereafter, the mixed air is blown into the vehicle interior portion asair conditioning wind.

An air conditioner ECU 50 is provided at the air conditioning controller26 of the air conditioner 30. A temperature after evaporator sensor 52which detects the temperature of the air which has passed through theevaporator 34 (the "temperature after evaporator"), and various sensorswhich are not shown and detect environmental conditions such as outsideair, vehicle interior temperature, amount of solar radiation, and thelike, are connected to the air conditioner ECU 50. The air conditionerECU 50 controls the air conditioner 30 and air-conditions the vehicleinterior portion, on the basis of detected results by these sensors andoperating conditions such as setting temperature or the like which isset by passengers operating an operating panel (not shown) provided assetting means.

At this time, the air conditioner ECU 50 sets the temperature afterevaporator on the basis of environmental conditions and operatingconditions, and controls the compressor 32 such that the air, which haspassed through the evaporator 34, is at the temperature afterevaporator. When blowout temperature (a target blowout temperature) isset to regulate the temperature of the vehicle interior portion to asetting temperature, the air conditioner ECU 50 controls the air mixdamper 46 so as to obtain the blowout temperature.

A conventionally known mechanism and control method which are used for ahybrid car as well as various vehicles can be applied to a mechanism anda control method for optimally air-conditioning the vehicle interiorportion, and a detailed description thereof will be omitted.

The air conditioner ECU 50 is connected to the engine ECU 24. The airconditioner ECU 50 switches ON the electromagnetic clutch 36 inaccordance with the driving of the compressor 32 and outputs a "startengine" signal to the engine ECU 24.

When the engine ECU 24 receives a "start engine" demand outputted froman apparatus such as the air conditioner ECU 50 or the like while theengine 12 is stopping, the engine ECU 24 starts the engine 12. While theengine ECU 24 is driving the engine 12 by receiving a "start engine"demand from an external apparatus, in a case in which a "start engine"demand is canceled or stopping of the "start engine" demand isoutputted, the engine ECU 24 stops the engine 12.

The air conditioner ECU 50 reads a traveling rate of the vehicle 10,which is output from the engine ECU 24 and judges whether the vehicle 10is traveling or stopping. Namely, the engine ECU 24 serves as detectingmeans and is connected to the air conditioner ECU 50. A vehicle speedsensor or the like may be used as detecting means.

As an operation of the present embodiment, an example of a "startengine" demand for the engine 12 outputted from the air conditioner ECU50 will be explained hereinafter with reference to a flowchart which isshown in FIG. 2.

As described above, when the air conditioner 30 is instructed to operateby setting means (not shown), the air conditioning of the vehicleinterior portion is effected on the basis of environmental conditionsand setting conditions. At this time, when the compressor 32 must bedriven, the air conditioner ECU 50 outputs a "start engine" demand tothe engine ECU 24. When the vehicle 10 stops, the engine ECU 24 stopsthe engine 12 so as to save power energy. When the engine ECU 24receives a "start engine" demand from the air conditioner ECU 50 or thelike, the engine ECU 24 starts the engine 12. When a "start engine"demand is terminated entirely, the engine ECU 24 stops the engine 12.

With reference to a flowchart in FIG. 2, a description of a "startengine" demand outputted from the air conditioner ECU 50 to the engineECU 24 will be given hereinafter.

This flowchart executes the routine when the air conditioner 30 isswitched ON by an operation switch provided at setting means (notshown), while it terminates the routine when the air conditioner 30 isswitched OFF by the operational switch.

First, in Step 100, after flag F has been reset (F=0), the routine isexecuted. Next, in Step 102, it is judged whether the vehicle 10 istraveling. Namely, it is judged whether a speed S outputted from theengine ECU 24 equals to S=0.

When the vehicle 10 is traveling, because the speed equals to S≠0, thejudgment is negative in Step 102, and the routine goes to Step 104. InStep 104, the temperature after evaporator T_(E) is compared with apredetermined temperature (a first temperature) T₀. The temperatureneeded for minimum cooling capacity by the evaporator 34 is preset asT₀. It is desirable that cooling performance at the minimum of necessitycan be obtained by the aforementioned temperature T₀. It is alsodesirable that the temperature T₀ suffices that the differences betweenhumidities of blowout air are not increased. The temperature T₀ may be avariable value which decreases as cooling load increases.

When the temperature after evaporator T_(E) is equal to or lower thanthe temperature T₀ (T_(E) ≦T₀), it is judged that the cooling capacityis reliably maintained. The routine goes to Step 106 where a "startengine" demand is not outputted, and exits the flowchart.

When the temperature after evaporator T_(E) is higher than thetemperature T₀ (T_(E) ≧T₀), it is judged that sufficient coolingcapacity is not maintained. The routine goes to Step 108 where a "startengine" demand is effected for the engine ECU 24. Namely, a signalrepresenting a "start engine" demand is output to the engine ECU 24. Atthe same time, the air conditioner 50 switches ON the electromagneticclutch 36 so as to drive the compressor 32 due to the driving force fromthe engine 12.

When the engine ECU 24 receives a "start engine" demand outputted fromthe air conditioner ECU 50, in a case in which the engine 12 stops, theengine ECU 24 drives the engine 12. Accordingly, the driving force istransmitted from the engine 12 to the compressor 32 so that thetemperature after evaporator T_(E) is decreased.

When the vehicle is stopping, the judgment is affirmative in Step 102,the routine goes to Step 110. In Step 110, the aforementionedtemperature T₀ and a target blowout temperature (a second temperature)T_(A0) are compared with each other.

When the target blowout temperature T_(A0) is equal to or lower than thetemperature T₀, the routine goes to Step 112 where the temperature afterevaporator T_(E) is compared with the temperature T₀. When thetemperature after evaporator T_(E) is higher than the temperature T₀(T_(E) >T₀), the routine goes to Step 114 where flag F is set (F=1).Thereafter, a "start engine" demand is outputted to the engine ECU 24(Step 116). When the vehicle 10 stops and the engine 12 stops, theengine ECU 24 starts the engine 12 in response to a "start engine"demand. Accordingly, the compressor 32 is driven and the temperatureafter evaporator T_(E) is lowered.

When the temperature after evaporator T_(E) is equal to or less than thetemperature T₀, it is judged that a cooling capacity by the evaporator34 can be reliably maintained. The routine goes to Step 120.

When a target temperature T_(A0) is higher than the temperature T₀, theroutine goes from Step 110 to Step 118, where the temperature afterevaporator T_(E) and a target blowout temperature T_(A0) are comparedwith each other.

When the temperature after evaporator T_(E) is higher than the targetblowout temperature T_(A0), it is judged that a cooling capacity is notsufficient. In Step 114, flag F is set. Thereafter, a "start engine"demand is outputted by the engine ECU 24 (Step 116).

In this way, only when the temperature after evaporator T_(E) is higherthan the temperature set for obtaining minimum cooling capacity withoutdriving the compressor 32, a "start engine" demand is outputted. Forthis reason, unnecessary starting up of the engine 12 while the vehicle10 is stopping and wasteful fuel consumption can be prevented.

When the temperature after evaporator T_(E) is equal to or lower thanthe temperature which is set for obtaining minimum cooling capacitywithout driving the compressor 32 (Step 112: T_(E) ≦T₀, Step 118: T_(E)≦T_(A0)), it is judged that minimum cooling capacity is maintained andthe routine goes to Step 120.

In Step 120, it is judged whether flag F is in a reset state. Flag F isreset when the vehicle 10 starts to travel. In other words, when theengine 12 is started for the vehicle 10 to travel, flag F is reset.However, in a state in which the vehicle 10 stops, flag F is set when a"start engine" demand for the engine 12 is outputted to the engine ECU24.

In Step 120, it is judged whether a "start engine" demand is outputtedafter the vehicle 10 has stopped. When flag F is in a reset state, thejudgment is affirmative in Step 120, and the routine goes to Step 122,where a "start engine" demand is not outputted, and the routine exitsthe flowchart. In this state, the engine 12 is stopped by a demand(stopping of the "start engine" demand) from the air conditioner ECU 50.

A state in which flag F is set is a state in which a "start engine"demand has already been outputted and the engine 12 has already started.At this time, the judgment is negative in Step 120, and the routine goesto Step 116 where a "start engine" demand is outputted. At least, thestate in which the engine 12 is started by stopping of "start engine"demand by the air conditioner ECU 50 should be maintained.

Thus, after the vehicle 10 has stopped, once the engine 12 is started,it is desirable not to start the engine 12 uselessly. When the vehiclestops and the engine 12 also stops, it is estimated that noise may becaused at a low level. In this state, the engine 12 which keeps onstarting up when the vehicle 10 stops could annoy passengers. However,in accordance with the present embodiment, the aforementioned annoyancecausing to passengers can be prevented.

Further, while the vehicle 10 is stopping, when the engine 12 keeps onstarting up, after the time during which the engine 12 which keeps onstarting up does not seem to annoy passengers has passed (for example,between a few minutes and about ten minutes), flag F can be reset.Accordingly, it is judged whether cooling capacity is maintained. Whenthe cooling capacity is maintained, the routine goes to Step 122 wherethe engine 12 can be stopped.

Next, a description of a second embodiment of the present invention willbe given hereinafter. The present second embodiment is structured in thesame manner as the first embodiment, and a description thereof will beomitted.

Next, with reference to a flowchart shown in FIG. 3, a "start engine"demand for the engine 12 to the engine ECU 24 by the air conditioner ECU50 will be explained.

The routine in this flowchart is executed/terminated due to ON/OFFoperation of the air conditioner 30 which is operated by an operationswitch provided at setting means (not shown).

In Step 200 of FIG. 3, it is judged whether the vehicle 10 is traveling.Namely, it is judged whether a vehicle speed S outputted from the engineECU 24 is equal to 0 (S=0).

In a traveling state of the vehicle 10, a vehicle speed S outputted fromthe engine ECU 24 is not equal to 0 (S≠0). Accordingly, the judgment isnegative in Step 200, and the routine proceeds to Step 202.

In Step 202, it is judged whether the difference between the temperatureof the vehicle interior portion T_(R) and a setting temperature T_(S) ismore than a predetermined temperature A°. In a case in which thedifference between the temperature of the vehicle interior portion T_(R)and a setting temperature T_(S) is equal to or less than a predeterminedtemperature A°, the routine goes to Step 204 where a "start engine"demand is not outputted to the engine ECU 24, and exits this flowchart.

In a case in which the difference between the temperature of the vehicleinterior portion T_(R) and a setting temperature T_(S) is more than apredetermined temperature A°, the routine goes to Step 206 where a"start engine" demand is outputted to the engine ECU 24.

In a stopping state of the vehicle 10, the judgment is affirmative inStep 200 and the routine goes to Step 208. In Step 208, it is judgedwhether the difference between the temperature of the vehicle interiorportion T_(R) and a setting temperature T_(S) is more than apredetermined temperature A°. In a case in which the difference betweenthe temperature of the vehicle interior portion T_(R) and a settingtemperature T_(S) is more than a predetermined temperature A°, it isjudged that sufficient cooling capacity is not maintained. The routinegoes to Step 214 where a "start engine" demand is outputted to theengine ECU 24.

In a case in which the difference between the temperature of the vehicleinterior portion T_(R) and a setting temperature T_(S) is equal to orlower than a predetermined temperature A°, in Step 210, it is judgedwhether the temperature after evaporator T_(E) is more than apredetermined temperature B°.

In a case in which the temperature after evaporator T_(E) is more than apredetermined temperature B°, it can be determined that the temperatureis more than a maximum value of a range of the temperature at which ahuman being usually feel comfortable. In this case, it is judged thatsufficient cooling capacity is not maintained. The routine goes to Step214.

In a case in which the temperature after evaporator T_(E) is less thanor equal to a predetermined temperature B°, it can be judged thatsufficient cooling capacity is maintained through the evaporator 324.The routine proceeds to Step 212 and exits the flowchart withoutoutputting a signal of a "start engine" demand.

In a case in which the difference between the temperature of the vehicleinterior portion T_(R) and the setting temperature T_(S) is equal to orlower than a predetermined temperature A° and the temperature afterevaporator T_(E) is equal to or lower than the predetermined temperatureB°, a "start engine" demand is not outputted. The engine 12 can bestarted at the minimum of necessity. Accordingly, the amount of fuelconsumed can be reduced.

The aforementioned first and second embodiments show an example of thepresent invention, and the structures of a hybrid car and an airconditioner according to the present invention are not limited to thoseembodiments. The present invention is applicable to an air conditioningcontroller provided in a hybrid car which has various structures and candrive the engine at a maximum efficiency by using an assist motor.

What is claimed is:
 1. An air conditioning controller for a hybrid car,which is provided in the hybrid car being equipped with an engine and anelectric motor and having starting means for starting the engine inresponse to a "start engine" demand, and which controls an airconditioner for air-conditioning a vehicle interior portion via acooling cycle formed by a compressor and an evaporator,comprising:temperature after evaporator detecting sensor which detectsthe temperature of air cooled by said evaporator; judging means whichjudges whether the temperature after said evaporator detected by saidtemperature after evaporator detecting sensor is equal to or lower thana predetermined temperature; and stopping means which stops said "startengine" demand when the temperature after said evaporator detected bysaid temperature after evaporator detecting sensor is judged to be equalto or lower than a predetermined temperature.
 2. An air conditioningcontroller for a hybrid car according to claim 1, wherein in a case inwhich the temperature after evaporator detected by said temperatureafter evaporator detecting sensor is equal to or higher than apredetermined temperature, said starting means outputs an "start engine"demand.
 3. An air conditioning controller for a hybrid car according toclaim 1, wherein said predetermined temperature is a temperature atwhich it can be judged that minimum cooling capacity can be maintainedwithout driving the compressor.
 4. An air conditioning controller for ahybrid car according to claim 3, wherein said predetermined temperatureis the higher of the temperature needed for minimum cooling capacity andthe temperature of the blowout air at the time when the air-conditionedair is blown into the vehicle interior portion so that the temperatureof the vehicle interior portion is kept at a set temperature.
 5. An airconditioning controller for a hybrid car according to claim 1, whereinsaid judging means is structured by first judging means which judges thehigher of the temperature needed for minimum cooling capacity and thetemperature of the blowout air at the time when the air-conditioned airis blown into the vehicle interior portion so that the temperature ofthe vehicle interior portion is kept at a set temperature; and secondjudging means which judges whether said detected temperature after saidevaporator is equal to or lower than the temperature which has beenjudged to be higher by said first judging means.
 6. An air conditioningcontroller for a hybrid car according to claim 1, wherein saidpredetermined temperature is a value which decreases as the cooling loadincreases.
 7. An air conditioning controller for a hybrid car accordingto claim 1, wherein said starting means is an engine control computerfor driving the engine.
 8. An air conditioning controller for a hybridcar according to claim 1, wherein when it has been judged by saidjudging means that said temperature after said evaporator exceeds apredetermined temperature, stopping of said "start engine" demand bysaid stopping means is canceled and a "start engine" demand is given tosaid starting means.
 9. An air conditioning controller for a hybrid caraccording to claim 8, further comprising:detecting means for detectingwhether a vehicle has stopped or not,wherein in a case in which it hasbeen detected by said detecting means that the vehicle has stopped, theoperation of said stopping means is prohibited.
 10. An air conditioningcontroller for a hybrid car according to claim 9, wherein said stoppingmeans can be set to operate when said engine keeps on driving for apredetermined period of time.
 11. An air conditioning controller for ahybrid car according to claim 9, wherein said detecting means is anengine control computer which drives the engine, or a vehicle speedmeans which detects vehicle speed.
 12. An air conditioning controllerfor a hybrid car according to claim 10, wherein said detecting means isthe engine control computer or the vehicle speed means.
 13. An airconditioning controller for a hybrid car, which is provided in thehybrid car being equipped with an engine and an electric motor andhaving an engine control computer for starting the engine in response toa "start engine" demand, and which has a computer for an air conditionerwhich controls an air conditioner for air-conditioning a vehicleinterior portion via a cooling cycle formed by a compressor and anevaporator, comprising:temperature after evaporator detecting sensorwhich detects the temperature of air cooled by said evaporator; saidcomputer for an air conditioner judges whether the temperature aftersaid evaporator detected by said temperature after evaporator detectingsensor is equal to or lower than a predetermined temperature and stopsthe "start engine" demand when the temperature after said evaporatordetected by said temperature after evaporator detecting sensor is judgedto be equal to or lower than a predetermined temperature.
 14. An airconditioning controller for a hybrid car according to claim 13, whereinin a case in which the temperature after evaporator detected by saidtemperature after evaporator detecting sensor is equal to or higher thana predetermined temperature, said starting means outputs an "startengine" demand.
 15. An air conditioning controller for a hybrid caraccording to claim 13, wherein said predetermined temperature is atemperature at which it can be judged that minimum cooling capacity canbe maintained without driving a compressor.
 16. An air conditioningcontroller for a hybrid car according to claim 15, wherein saidpredetermined temperature is the higher of the temperature needed forminimum cooling capacity and the temperature of the blowout air at thetime when the air-conditioned air is blown into the vehicle interiorportion so that the temperature of the vehicle interior portion is keptat a set temperature.
 17. An air conditioning controller for a hybridcar according to claim 16, wherein said computer for an air conditionerjudges the higher of the temperature needed for minimum cooling capacityand the temperature of the blowout air at the time when theair-conditioned air is blown into the vehicle interior portion so thatthe temperature of the vehicle interior portion is kept at a settemperature and judges whether said detected temperature after saidevaporator is equal to or lower than the temperature which has beenjudged to be higher by the judgment, and thereby judges whether thetemperature after said evaporator detected by said temperature afterevaporator detecting sensor is equal to or lower than a predeterminedtemperature.
 18. An air conditioning controller for a hybrid caraccording to claim 15, wherein said predetermined temperature has atemperature which decreases as the cooling load increases.
 19. An airconditioning controller for a hybrid car, which is provided in thehybrid car being equipped with an engine and an electric motor andhaving starting means for starting the engine in response to a "startengine" demand, and which controls an air conditioner forair-conditioning a vehicle interior portion via a cooling cycle formedby a compressor and an evaporator, comprising:a temperature afterevaporator detecting sensor which detects the temperature of air cooledby said evaporator; a vehicle interior portion temperature detectingsensor which detects the temperature of the vehicle interior portion;first judging mean which judges whether the difference between thetemperature of the vehicle interior portion detected by said vehicleinterior portion temperature detecting sensor and a set temperature isgreater than a predetermined value; second judging means which judgeswhether the temperature after said evaporator detected by saidtemperature after evaporator detecting sensor is greater than apredetermined temperature in a case in which the result of the judgmentby said first judging means is negative; and stopping means which stopssaid "start engine" demand in a case in which the result of the judgmentby said second judging means is negative.
 20. An air conditioningcontroller for a hybrid car according to claim 19, wherein said startingmeans is an engine control computer which drives the engine.
 21. An airconditioning controller for a hybrid car according to claim 19, wherein,when the result of the judgment by said first judging means isaffirmative, and the result of the judgment by said second judging meansis affirmative, stopping of said "start engine" demand by said stoppingmeans is canceled and a "start engine" demand is given to said startingmeans.
 22. An air conditioning controller for a hybrid car according toclaim 21, wherein said detecting means is the engine control computerwhich drives the engine or the vehicle speed means which detects vehiclespeed.